How to Get Oxygen and Survive on Airless Planets

Craft the suit first

Oxygen in Ad Astra is handled by a suit-based system, not by breathing blocks. You need a full Space Suit set — helmet, chestplate, leggings, and boots — plus an Oxygen Tank that stores breathable air. The suit pieces are made from steel plates and other mod materials; the tank is a separate item you fill and equip. Without a complete suit, stepping onto the Moon or any airless body drains your oxygen bar almost immediately.

Fill and manage your tank

Oxygen Tanks are filled at an Oxygen Loader or similar station block placed on your base. Connect it to an oxygen source (the mod provides oxygen generation through its machinery chain) and insert the tank to top it off. Carry spare tanks in your inventory so you can swap when one runs dry. On planets with breathable atmospheres you can refill naturally, but on the Moon and most asteroids you must rely entirely on carried oxygen.

Build a safe base

Once you land, place an Airlock and seal a room with the mod's space-grade blocks so the interior becomes pressurized. Inside a sealed, airlocked structure you can remove your helmet safely. Always keep a spare Oxygen Tank and a return rocket fueled before you wander far from your lander.